Rotary cutter assembly for a pavement grooving machine

ABSTRACT

A rotary cutter head designed for use with tractionally driven pavement grooving machines. A large multiplicity of slightly spaced, radially disposed cutter disks having abrasive peripheries are clamped together by through bolts and mounted on a rotary tubular sleeve which is supported at its end on a fixed central supporting shaft by means of roller bearings. The assembly is driven by a pair of pulleys carried at the opposite ends of the sleeve and torque is applied from the pulleys to the sleeve through the medium of the through bolts which project through both pulleys, as well as through all of the cutter disks.

Assignee United States Patent Stafford M. Ellis Kent, England 391192?Apr. 16, 1970 Oct. 12, 1971 Concut, Inc. Toledo, Ohio Inventor Appl. No.Filed Patented ROTARY CU'I'IER ASSEMBLY FOR A PAVEMENT GROOVING MACHINEl 1 Claims, 5 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 3,376,673 4/1968 Metzger etal. 229/89 Primary Examiner-Ernest R. Purser Attorney-Norman H. GerlachABSTRACT: A rotary cutter head designed for use with tractionally drivenpavement grooving machines. A large multiplicity of slightly spaced,radially disposed cutter disks having abrasive peripheries are clampedtogether by through bolts and mounted on a rotary tubular sleeve whichis supported at its end on a fixed central supporting shaft by means ofroller bearings. The assembly is driven by a pair of pulleys carried atthe opposite ends of the sleeve and torque is applied from the pulleysto the sleeve through the medium of the through bolts which projectthrough both pulleys, as well as through all of the cutter disks.

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I'll-rill 5 Ow n PATENTEDnm 12 1911 INVENTOR STAFFORD M ELL/8 ROTARYCUTTER ASSEMBLY FOR A PAVEMENT GRoovrNc MACHINE The improved rotarycutter assembly comprising the present invention is designed primarilyfor use in connection with a tractional or vehicular concrete pavementgrooving machine of the type which is employed for creating antiskidsafety grooves in either concrete highways at strategic locations suchas at curves, overpasses and the like or in airport concrete runways.Exemplary of this type of machine is U.S. Pat. No. 3,269,775, granted onAug. 30, 1966. The invention is not necessarily limited to use inconnection with a machine whose primary function is to cutconstant-depth safety grooves in concrete and the principles of theinvention may, with or without modification as required, be employed inconnection with pavement levelling machines of the type which iscommonly referred to as a bump cutter. Exemplary of such a machine areU.S. Pat. No. 3,007,687, granted on Nov. 7, 1961 and the U.S. Pat. No.3,195,957, granted on July 20, 1965. Irrespective, however, of theparticular use to which the invention may be put, the essential featuresthereof are at all times preserved.

The invention is concerned primarily with an improved rotary cuttingassembly which, without departing from the principles of the invention,may be constructed for use either to cut constant-depth safetygrooves ina pavement or to level the pavement. In general, such a cuttingassembly, as well as that of the present invention, embodies a rotarymandrel having mounted thereon in axially-spaced relationship amultiplicity of disklike cutters, such cutters having abrasive segmentson the peripheries thereof being comprised of individual metallicmatrices containingcrushed orfragmented diamonds or other abrasiveparticles, and serving in connection with the intended use of theassembly to cut parallel groovesin the pavement. The axial spacing ofthe cutters is determined by the nature of the operation to be performedon the pavement. Where constant-depth skid-reducing or safety groovesare desired, the spacing between the cutters is'relatively wide, whereaswhen pavement levelling is resorted to, the spacing between cutters isrelatively close. In either event, the cutters are maintained in theirspaced relation by spacer members which are interposed between adjacentcutters. In one type of rotary cutter assembly, these spacer members arein the'form of annular or ring-shaped spacer rings which encompass themandrel of the assembly and are concentric therewith while a series ofcircumferentially spaced clamping bolts project through the entireseries of cutters and spacer rings and clamp them all together in anaxial direction. In another type ofrotary cutter assembly, the spacermembers are in the form of individual washers which are interposedbetween adjacent cutters and surround the clamping bolts. With all typesof rotary cutter assemblies, a coolant (preferably water) is deliveredto the outer peripheries of the cutters, usually by externallypositioned spraying devices, but sometimes by internal feeding of thecoolant through a hollowcentral mandrel.

As evidenced by U.S. Pat. No. 3,376,673, granted on Apr. 9, 1968, it hasheretofore been the practice to journal the rotary mandrel of a rotarycutter assembly in bearings at the opposite ends thereof and to effectrotation of the mandrel and its cutters by providing an overhangingmultiple groove pulley on one end of the mandrel or on an extensiononone end of the mandrel, such pulley being disposed outwards of theadjacent bearing. Such an arrangement has not proven altogethersatisfactory inasmuch as the tremendous frictional resistance which isoffered to the cutters as a group places excessive torque on the mandrelin the region thereof between the pulley and the adjacent group ofcutters thereby resulting in frequent rupture of the mandrel in suchregion. Additionally, due to exposure of the bearings for the mandrel tothe products of abrasion, such bearings are possessed of a relative lyshort life. Finally, the relatively small diameter mandrel tends to flexduring operation of the assembly due to side loads which may be imposedthereon by reason of irregularities or rises in the pavement undergoingtreatment so that the .bolts, instead of being'mounted directly on acentral rotatable mandrel, are mounted on a rotary mounting sleevewhich, in turn, is rotatable on a centrally disposed fixed nonrotatableshaft by means of internal bearings which are interposed between themounting sleeve and the nonrotatable shaft near the ends of the sleeves,the mounting sleeve being driven by means of a pair of multiple groovepulleys at the ends of the sleeve. By such an arrangement, anoverhanging pulley is avoided, the bearings are concealed, andthus,.protected from water and the products of abrasion, and torque isapplied to the cutter bluster from both ends thereof.

A further feature of the improved rotary cutter assembly constitutingthe present invention resides in the provision of a centralspacer memberwhich is affixed to the mounting sleeve and divides the cutter clusterinto two parts, one on each side of the fixed spacer member. Anadvantage of this feature residesin the fact that in assembling thecutter cluster, the cutter. blades and the washerlike spacer members canbe loaded on the mounting sleeve from both ends, while functionally thecentral fixed'spacer member constitutes, inefiect, acentral-torque-transmitting drive for the cutter cluster, in addition tothe two end drives therefor. I

The primary object of. the invention is to provide a rotary cutterassembly which is characterized by high efficiency and low cost ofproduction and is an improvement upon, and eliminates the various andsundry disadvantages of, previously designed rotary cutter assembliesincluding that of aforementioned U.S. Pat. No. 3,376,673. Other objectsof the invention will be noted'from a consideration of the followingdetailed description.

The invention consists in the several novel features which arehereinafter set'forth and are more particularly defined by being shownoperatively supported in end frame members which constitute a part ofthe pavement grooving machine with which the cutter assembly is adaptedto be associated;

FIG. 2 is an enlarged, fragmentary transverse sectional view taken onthe line 22 of FIG. 1; I

FIG. 3 is an enlarged, fragmentary, longitudinal, sectionalview of theassembly;

FIG. 4' is an enlarged, fragmentary, transverse sectional view taken onthe line 4-4 of FIG. 3; and

FIG. 5 is an enlarged, fragmentary sectional view of one of the cuttersof the assembly.

Referring now to the drawings in detail, and in particular to FIGS. 1and 2, the rotary cutter assembly of the present invention is designatedin its entirety by the reference numeral 10 and is shown as beingoperatively mounted on the frame of a pavement grooving machine, theframe being represented by two laterally spaced-apart frame members 12which constitute the sole support for the assembly.

The cutter assembly 10 involves in its general organization afrxedcentral supporting shaft 14 (see FIG. 3) which extends between thetwo frame members 12 and is secured thereto at its ends in a manner thatwill .be described presently. The supporting shaft 14 is preferablyformed of steel and the opposite end regions thereof are of reducedstepped configuration, the step arrangement at each end of the shaftbeing the same so that a description of one end region of the shaft willsuffice for the other. Considering the right-hand reduced stepped endarrangement of the shaft 12 as viewed in FIG. 3, first, second and thirdstep reductions are provided, these reductions establishing a firstshaft surface area 16, a second shaft surface area 18, and a third orouter shaft surface area 20. The outer shaft surface area 20 projectsinto a circular hole 22 in the adjacent frame member 12 and is securedtherein by means of a stud 24 which is threadedly received in a socket26 in the end of the shaft. Said stud has mounted thereon a nut 25 whichbears against a split lock washer 28, the latter in turn bearing againsta fiat washer 30.

Surrounding the fixed supporting shaft 14 and concentric therewith is arotatable cutter mounting drive sleeve 32, the axial extent of which isslightly less than that of the supporting shaft 14. Interposed betweenthe mounting drive sleeve 32 and the supporting shaft 14 at each end ofthe cutter assembly is a roller bearing and seal arrangement, the twoarrangements being substantially identical so that a description of oneof them will suflice for them both. Each such roller bearing and sealarrangement includes a roller bearing assembly 40 having inner raceparts 42 which seat on the reduced shaft area 18, and, in addition,outer race parts 44 which seat in a recessed counterbore 46 in theadjacent end of the mounting drive sleeve 32. The roller bearingassembly 40 is straddled by a pair of labyrinth-type sealing ringsincluding an inner ring 48 which cooperates with the first shaft surfacearea 16 and an outer ring 50 which cooperates with the second shaftsurface area 18. The inner sealing ring 48 is confined between anannular shoulder 52 at the inner end of the counterbore 46 and the outerrace parts 44 of the bearing assembly 40. The outer sealing ring 50 isheld in place against the adjacent end or rim of the mounting drivesleeve 32 by clamping bolts 54 the inner ends of which extend intothreaded sockets in the adjacent end of the sleeve 32. The rollerbearing assembly 40 is confined between the outer sealing ring 50 and anannular shoulder 55 which exists between the shaft areas 16 and 18.

Means are provided for applying torque to both end regions of the cuttermounting drive sleeve 32 and, accordingly, two multiple groove pulleys56 are disposed on the opposite end regions of the sleeve and a drivingconnection is provided between each of these pulleys and the sleeve, aswill become apparent presently.

Telescopically received over the cutter mounting drive sleeve 32 arealternately arranged disklike cutters 60 and spacer rings 62. As shownin FIG. 1, there is a multiplicity or large number of the cutters andthe spacer rings. Each cutter is in the form of a circular steel disk 63(see FIGS. 2, 4 and 5) which has a central mounting hole 64 therein (seeFIG. 3) and is provided with a series of radial notches 66 in theperiphery thereof, the notches being equally and circumferentiallyspaced and serving to divide the peripheral region of the disk 63 intointervening sections 68. Each section 68 has affixed thereto by a silversoldering or similar operation an abrasive or cutter segment 70 whichpreferably is in the form of an arcuate sintered metal matrix withinwhich there is dispersed substantially uniformly a quantity offragmented diamonds or other abrasive material. Each cutter segment 70is preferably coextensive with the arcuate extent of its associatedsection 68 and the side portions thereof overhang the opposite sideedges of the disk as clearly shown in FIG. 5 and as is well known in theart of constructing peripheral diamond saw blades. The various notches66 are provided for the purpose of isolating the heat which is appliedto the periphery of the disk 63 during the soldering operation andpreventing the consequent thermal expansion from causing buckling of thedisk.

Each disklike cutter 60 have formed therein an annular series of holes72 (see FIGS. 2, 3 and 5) which, preferably, are four in number. Theseholes register with similar hole 74 (see FIGS. 3 and 4) in the spacerrings 62. Clamping bolts 76 project through the registering holes 72 and74 and also project through aligned bores 78 in a pair of relativelywide spacer members 80, as well as through aligned bores 82 in the twopulleys 56. The clamping bolts 76 are provided with nuts 84 at theopposite ends thereof, these nuts bearing against the outer end surfacesof the pulleys 56. The spacer members are constrained to rotate inunison with the mounting drive sleeve 32 by means of keys 86 (see FIG.4) which are secured by radially extending screws 88 to said mountingdrive sleeve. The spacer members 80 thus serve to transmit to theclamping bolts 76 and, consequently, to all of the cutters 60 and thespacer ring 62 the torque which is applied by the mounting drive sleeve32.

The central portion of the mounting drive sleeve 32 is provided with anexternal raised rib 90 (see FIG. 3) to which there is welded a centralring-shaped spacer member 92, the latter constituting, in effect, aradial reaction flange and being provided with bores 94 through whichthe central portions of the clamping bolts 76 project. Said spacermember 92, being fixed with respect to the mounting drive sleeve 32,serves to divide the cutters 60 and their associated spacer rings 62into two clusters, each of which is compressed between the spacer member92 and one of the nuts 84 on the clamping bolt. Relatively thin linerrings 96 are interposed between the spacer member 92 and each adjacentcutter 60. The central spacer member 90 not only maintains the variouscutters and spacer rings centered on the supporting shaft 14 in alongitudinal direction, but it facilitates cutter loading of themounting drive sleeve from either end.

In the operation of the herein described rotary cutter assembly 10, itwill be understood that as is customary in connection with similarcutter assemblies for the same purpose, the assembly will be mountedadjacent to the rear end of the pavement grooving machine of which itconstitutes a part, and also that during the course of any givenpavement grooving operation, the rotary cutter assembly will receive itsdownward thrust from the two frame members 12 so that the assembly bearsthe weight of substantially one-half the total weight of the pavementgrooving machine with which the frame members are associated. It iscontemplated that the operator's cab for the machine will be mounteddirectly above the cutter assembly 10 so that the weight of the operatorwill also constitute a thrust factor in maintaining a high pressure ofthe cutters 60 against the pavement. By such an arrangement, the thrustload upon the cutter assembly is borne by the two roller bearingassemblies 40, one at each end of the central fixed supporting shaft 14so that this shaft is substantially free from forces tending to flex it.Because the cutters 60 are mounted on the mounting drive sleeve 32instead of on the usual solid central drive spindle, the tremendoustwisting torque which frequently caused rupture of the spindle isobviated and such twisting torque as is applied to the mounting drivesleeve 32 is relatively small, especially since the sleeve is drivenfrom both ends thereof. Finally, it is to be noted that the applicationof torque to the cutter assembly as a whole is practically a peripheraldrive in that the torque is applied by the two pulleys 56 to theclamping bolts 76 which are disposed an appreciable radial distanceoutwardly from the central axis of the cutter assembly. These clampingbolts also render the cutter assembly rigid and cause the cutters to runtrue so that they will not deviate from the linearly straight grooveswhich they are intended to cut in the pavement, this being the casebecause the clamping action which is exerted by the bolts is at pointswhich are spaced radially outwardly from the mounting drive sleeve 32and close to the diamond impregnated abrasive segment 70. This affordsgreater support for the abrasive peripheries of the segments andprevents flutter thereof when they are operating in the grooves at highspeed.

The invention is not to be limited to the exact arrangement of partsshown in the accompanying drawings or described in this specification asvarious changes in the details of construction may be resorted towithout departing from the spirit or scope of the invention. Forexample, if desired, the annular spacer rings 62 may be replaced withindividual disklike washers which surround the clamping bolts 76, suchan arrangement contributing to the absence of sludge accumulationbetween the cutter disks 63.

Having thus described the invention what I claim as new and desire tosecure by letters patent is:

1. A rotary cutter assembly adapted for grooving pavement or the likeand comprising an elongated horizontally disposed supporting shafthaving means at its opposite ends whereby it may be fixedly secured to apair of spaced-apart frame members forming parts of a pavement groovingmachine, a generally cylindrical rotary cutter mounting drive sleeveencompassing said shaft in coaxial relationship and substantiallycoextensive therewith, said mounting drive sleeve being wholly supportedby said shaft and rotatable thereon, a series of longitudinally spaced,relatively thin, flat, annular disklike cutters encircling said mountingdrive sleeve, disposed in radial planes, and slidable axially on saidsleeve, spacer members interposed between adjacent cutters and servingto maintain the same in their longitudinally spaced relationship, aseries of circumferentially spaced clamping bolts positioned radiallyoutwardly from said mounting drive sleeve, extending through saidcutters and spacers and serving to compress the same together andrigidify the cutters, reaction means preventing longitudinal shifting ofsaid cutters and spacers on the mounting drive sleeve, means forapplying torque to said mounting drive sleeve to drive the same, andmeans establishing a driving connection between said mounting drivesleeve and said cutters.

2. A rotary cutter assembly as set forth in claim 1 and wherein saidmeans for applying torque to the mounting drive sleeve comprises a drivepulley mounted on said mounting drive sleeve adjacent to each endthereof.

3. A rotary cutter assembly as set forth in claim 2 and wherein saidmeans establishing a driving connection between the mounting drivesleeve and cutters comprises a key operatively disposed between at leastone of said spacers and the sleeve.

4. A rotary cutter assembly as set forth in claim 3 and wherein thereaction means for preventing longitudinal shifting of the cutters andspacers comprises a radial reaction flange on said mounting drive tubethrough which said clamping bolts project.

5. A rotary cutter assembly as set forth in claim 4 and wherein saidreaction flange constitutes one of said spacers and is disposed betweena pair of adjacent cutters on the-medial region of the mounting drivesleeve.

6. A rotary cutter assembly as set forth in claim 5 and wherein theclamping bolts project completely through all of the cutters and spacersand also through said drive pulleys.

7. A rotary cutter assembly as set forth in claim 6 and wherein all ofsaid cutters and spacers are disposed between said drive pulleys, andthe clamping bolts are provided with nuts on the opposite ends thereofwhich bear against the outer ends of the drive pulleys.

8. A rotary cutter assembly as set forth in claim 6 and including,additionally, roller bearing assemblies interposed between said mountingdrive sleeve and the fixedly secured supporting shaft and positionedadjacent to the opposite ends of the shaft.

9. A rotary cutter assembly as set forth in claim 8 and wherein each ofsaid roller bearing assemblies is disposed substantially entirely withinthe radial confines of an adjacent drive pulley.

10. A rotary cutter assembly as set forth in claim 9 and including,additionally, pairs of labyrinth-type sealing rings interposed betweenthe mounting drive sleeve and the fixedly secured supporting shaft andstraddling the roller bearing assemblies respectively.

11. A cutter assembly as set forth in claim 10 and wherein said fixedlysecured supporting shaft is substantially symmetrical with respect toits midpoint and each end thereof is of stepped configuration providingfirst, second and third reduced shaft surface areas, said first surfacearea cooperating with one of said labyrinthtype sealing rings, saidsecond surface area cooperating with the adjacent roller bearingassembly in supporting relationship and also with the other labyrinthsealing ring, and the third surface area constituting a pilot post bymeans of which the adjacent end of the shaft is supported from theadjacent frame member.

1. A rotary cutter assembly adapted for grooving pavement or the likeand comprising an elongated horizontally disposed supporting shafthaving means at its opposite ends whereby it may be fixedly secured to apair of spaced-apart frame members forming parts of a pavement groovingmachine, a generally cylindrical rotary cutter mounting drive sleeveencompassing said shaft in coaxial relationship and substantiallycoextensive therewith, said mounting drive sleeve being wholly supportedby said shaft and rotatable thereon, a series of longitudinally spaced,relatively thin, flat, annular disklike cutters encircling said mountingdrive sleeve, disposed in radial planes, and slidable axially on saidsleeve, spacer members interposed between adjacent cutters and servingto maintain the same in their longitudinally spaced relationship, aseries of circumferentially spaced clamping bolts positioned radiallyoutwardly from said mounting drive sleeve, extending through saidcutters and spacers and serving to compress the same together andrigidify the cutters, reaction means preventing longitudinal shifting ofsaid cutters and spacers on the mounting drive sleeve, means forapplying torque to said mounting drive sleeve to drive the same, andmeans establishing a driving connection between said mounting drivesleeve and said cutters.
 2. A rotary cutter assembly as set forth inclaim 1 and wherein said means for applying torque to the mounting drivesleeve comprises a drive pulley mounted on said mounting drive sleeveadjacent to each end thereof.
 3. A rotary cutter assembly as set forthin claim 2 And wherein said means establishing a driving connectionbetween the mounting drive sleeve and cutters comprises a keyoperatively disposed between at least one of said spacers and thesleeve.
 4. A rotary cutter assembly as set forth in claim 3 and whereinthe reaction means for preventing longitudinal shifting of the cuttersand spacers comprises a radial reaction flange on said mounting drivetube through which said clamping bolts project.
 5. A rotary cutterassembly as set forth in claim 4 and wherein said reaction flangeconstitutes one of said spacers and is disposed between a pair ofadjacent cutters on the medial region of the mounting drive sleeve.
 6. Arotary cutter assembly as set forth in claim 5 and wherein the clampingbolts project completely through all of the cutters and spacers and alsothrough said drive pulleys.
 7. A rotary cutter assembly as set forth inclaim 6 and wherein all of said cutters and spacers are disposed betweensaid drive pulleys, and the clamping bolts are provided with nuts on theopposite ends thereof which bear against the outer ends of the drivepulleys.
 8. A rotary cutter assembly as set forth in claim 6 andincluding, additionally, roller bearing assemblies interposed betweensaid mounting drive sleeve and the fixedly secured supporting shaft andpositioned adjacent to the opposite ends of the shaft.
 9. A rotarycutter assembly as set forth in claim 8 and wherein each of said rollerbearing assemblies is disposed substantially entirely within the radialconfines of an adjacent drive pulley.
 10. A rotary cutter assembly asset forth in claim 9 and including, additionally, pairs oflabyrinth-type sealing rings interposed between the mounting drivesleeve and the fixedly secured supporting shaft and straddling theroller bearing assemblies respectively.
 11. A cutter assembly as setforth in claim 10 and wherein said fixedly secured supporting shaft issubstantially symmetrical with respect to its midpoint and each endthereof is of stepped configuration providing first, second and thirdreduced shaft surface areas, said first surface area cooperating withone of said labyrinth-type sealing rings, said second surface areacooperating with the adjacent roller bearing assembly in supportingrelationship and also with the other labyrinth sealing ring, and thethird surface area constituting a pilot post by means of which theadjacent end of the shaft is supported from the adjacent frame member.